public bool GetDisplacement(float x, float z, out Vector3F displacement, out Vector3F normal)
{
if (!EnableCpuQueries)
{
throw new InvalidOperationException("OceanWaves.GetDisplacement() can only be called if EnableCpuQueries is set to true.");
}
displacement = new Vector3F(0);
normal = new Vector3F(0, 1, 0);
if (_h == null)
{
return(false);
}
float texCoordX = (x - TileCenter.X) / TileSize + 0.5f;
float texCoordY = (z - TileCenter.Z) / TileSize + 0.5f;
// Point sampling or bilinear filtering:
#if false
// Convert to array indices.
int xIndex = Wrap((int)(texCoordX * CpuSize));
int yIndex = Wrap((int)(texCoordY * CpuSize));
float h = _h[xIndex, yIndex].X;
Vector2F d = _D[xIndex, yIndex];
Vector2F n = _N[xIndex, yIndex];
#else
// Sample 4 values. The upper left index is (without wrapping):
float xIndex = texCoordX * CpuSize - 0.5f;
float yIndex = texCoordY * CpuSize - 0.5f;
// Get the 4 indices.
int x0 = Wrap((int)xIndex);
int x1 = Wrap((int)xIndex + 1);
int y0 = Wrap((int)yIndex);
int y1 = Wrap((int)yIndex + 1);
// Get fractions to use as lerp parameters.
float px = MathHelper.Frac(xIndex);
float py = MathHelper.Frac(yIndex);
float h = InterpolationHelper.Lerp(InterpolationHelper.Lerp(_h[x0, y0].X, _h[x1, y0].X, px),
InterpolationHelper.Lerp(_h[x0, y1].X, _h[x1, y1].X, px),
py);
Vector2F d = InterpolationHelper.Lerp(InterpolationHelper.Lerp(_D[x0, y0], _D[x1, y0], px),
InterpolationHelper.Lerp(_D[x0, y1], _D[x1, y1], px),
py);
Vector2F n = InterpolationHelper.Lerp(InterpolationHelper.Lerp(_N[x0, y0], _N[x1, y0], px),
InterpolationHelper.Lerp(_N[x0, y1], _N[x1, y1], px),
py);
#endif
displacement = new Vector3F(-d.X * Choppiness, h, -d.Y * Choppiness);
normal = new Vector3F(-n.X, 0, -n.Y);
normal.Y = (float)Math.Sqrt(1 - normal.X * normal.X - normal.Y * normal.Y);
return(true);
}